Process for silicating



Patented Jan. 19, 1932 UNITED STATES OLIVER 1B. ANDREWS,.OF CHAT'I'ANOOGA, TENNESSEE PROCESS FOR SILICATING No Drawing.

This invention relates to fiber board and to a process for manufacturing the same.

The invention is particularly applicable to the manufacture of a stron waterproof 5 fiber board, and provides for suitably coating and impregnating the board to materially increase the strength thereof and at the same time to render the board impervious to moisture.

It has been found that fiber board, particularly when employed in the manufacture of paper boxes is comparatively unstable and possesses relatively little strength. This is due in a large extent to the fact that the fiber board readily absorbs moisture from the air and becomes softened. This permits the board to crumple, and if the board is built up from a plurality of layers may even cause a separation of the various layers.

In forming a strong fiber board suitable for use in large boxes it is of course essential to so form the stock that acomparatively stiff product will be obtained... This may be accomplished by employing a plurality of laminations and securing them firmly together to form a heavy board. It has been found, however,that such a board is not, sufliciently strong to be utilized as a large'sized container for comparatively heavy articles without further treatment. J p

The present invention provides for so treating a fiber board as. to materially increase the strength thereof and to render the same suitable for use in large sized containers. The invention also provides for waterproofing the surface of the board so that the containers will be impervious to moisture and will maintain the contents thereof in substantially its original state.

The invention further consists in the new and novel features of operationand the new and original'arrangements and combinations of steps in the process hereinafter described and more particularly set forth in the claims.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claim appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization Application filed August 15, 1929. Serial No. 888,238.

may be better understood by referring to the following description in which a particular commercial embodiment thereof is disclosed. It will be understood, however, that the proc-. esses and the steps thereof may be modified in various respects without departing from the broad spirit and scope of the invention.

In the following description and in the claim the various steps in the process and the details comprising the invention will be identified by specific names for convenience butthey are intended to be as generic in their ap lication as the art will permit.

11 carrying out the present process it is desirable to apply the coating composition to the board in such manner that an even coating is obtained, and it is essential to carry out the drying operation so as toavoid warping of the board and at the same time permit the necessary penetration of the coating material. This may be accomplished by passing the board, which has previously been formed from a plurality of laminations which are secured together by any well known means, through a series of rollers or other device by means of which the solution may be applied.

It has been found that a solution of sodium silicate is particularly suitable for this purpose, although it'is obvious that other equivalent solutions may be utilized if desired. A 40 Baume solution of sodium silicate has been employed since this material is quick drying and imparts a particularly hard surface to the board. The silicate solution is capable of penetrating a slight distance into the board and in fact forms a layer of hard material on the surface thereof. This material is sufficiently rigid to materially increase the strength of the board andat the same time is impervious to moisture.

The silicate solution is applied by passing the board through rolls as abovementioned, or may be applied by other suitable means, such as spraying. The quantity, however, must be so regulated that the board may be readily dried and at the same time the coating must be suificiently heavy to produce the desired strengthening and waterproofing effect.

It has been found that if the board is passed between rollers which di into the silicate solution and are maintained at a temperature of substantially F a coating is applied which will dry in approximately 24 hours. During the drying process the boards are preferably stacked with separators of inactive material, such as praflined laths. The boards are preferably stacked vertically with the grain running in a vertical direction so that the tendency to warp is reduced to a minimum. During the drying operation a temperature of approximately 70 F. is maintained since it has been found that this temperature serves to completely dry out the material and at the same time does not produce excessive warping.

After the board has been prepared as above described it is suitable for manufacture into packing cartons of large size. In a specific instance cartons were manufactured which compared favorably in strength with thin wood and were capable of being used in fields which heretofore had required wooden crates.

The invention is not to be limited to the use of the particular coating material specified or the particular composition thereof, but only in accordance with the scope of the invention as defined by the following claim.

What is claimed is:

The process of forming a strong waterproof fiber board from a comparatively weak fiber board composed of a plurality of laminations rigidly secured together which comprises applying to the surface of said board a substantial 40 B. solution of sodium silicate maintained at approximately 70 F. and cansing said solution to penetrate a slight distance into the outer laminations and to rigidly adhere thereto and to form a coating on the surface thereof and drying said board by stacking the boards vertically with the grain running in a Vertical direction so that the tendency to warp is reduced to a minimum and maintaining thetemperature at approximately 70 F. during the drying process whereby a strong waterproof coating is applied which increases the strength of the board. and renders the same suitable for use as a container for heavy articles.

In testimony whereof I have hereunto set my hand.

OLIVER B. ANDREWS. 

